Single boom system having dual arm linkage

ABSTRACT

A control system is disclosed for use with a machine. The control system may have a first work tool connected at an end of a linkage arrangement, and a first interface device configured to receive input indicative of a desired movement of the first work tool and to generate a corresponding signal. The control system may also have a plurality of actuators operatively connected to the first work tool via the linkage arrangement, a plurality of valves associated with the plurality of actuators, and a controller in communication. The controller may be configured to determine a combination of the plurality of actuators that should be activated together to generate linkage movements that compound to produce the desired movement of the first work tool based on the signal, and to selectively command movement of a combination of the plurality of valves corresponding to the combination of the plurality of actuators.

TECHNICAL FIELD

The present disclosure relates generally to a machine system and, moreparticularly, to a single boom system having dual arm linkage.

BACKGROUND

An excavator is a well-known construction machine having a mobileundercarriage and an upper swing body pivotally connected to theundercarriage. Mechanical linkage is connected to the upper swing bodyand movable by hydraulic cylinders to raise, lower, and curl a worktool. The mechanical linkage typically includes a boom pivotallyconnected at a first end to the upper swing body, a stick or armpivotally connected to a second end of the boom, and the work toolconnected at a distal end of the stick. A pair of boom cylinders raisesand lowers the boom, while a single stick cylinder pivots the stickrelative to the boom. An additional tool cylinder is functional to curlthe tool relative to the stick. Many different tools can be connected tothe distal end of the stick and movable by the tool cylinder, dependingon the application of the excavator. These tools can include, amongothers, a bucket, a grapple, a shear, a hammer, a drill, a vibratorycompactor, an auger, a saw, and a pulverizer.

In some applications, it may be desirable to use two or more differenttools to accomplish a particular task. For example, in demolitionapplications, it may be helpful to use both a hammer and a bucket or agrapple and a shear. In these applications, either two machines must beplaced together to complete the task (each having a different tool), orthe tool of a particular machine must be periodically exchanged withanother tool. Both of these solutions can be expensive, inefficient,and/or time consuming.

An alternative solution is disclosed in U.S. Patent Publication2011/0150615 of Ishii that published on Jun. 23, 2011 (“the '615publication”). In particular, the '615 publication discloses anexcavator having two booms, two arms, and two work tools. Each linkagearrangement of boom, arm, and tool is pivotally connected to the upperstructure of the excavator and controllable by a separate operatorcontrol device. Each of the two linkage arrangements has a weight and apower that is about one-half of the weight and the power of aconventional single linkage arrangement.

Although the dual linkage arrangement of the '615 publication mayimprove efficiency somewhat, it may still be problematic. In particular,the machine of the '615 publication may no longer be useful inapplications that require the full power of the single linkagearrangement to perform a single lifting operation. In addition, controlof the two completely separate linkage arrangements may be complex anddifficult for the operator to become proficient at.

The disclosed machine system is directed to overcoming one or more ofthe problems set forth above and/or other problems of the prior art.

SUMMARY

One aspect of the present disclosure is directed to a control system foruse with a machine. The control system may include a first work toolconnected at an end of a linkage arrangement, and a first interfacedevice configured to receive input from an operator indicative of adesired movement of the first work tool and to generate a correspondingfirst work tool signal. The control system may also include a pluralityof actuators operatively connected to the first work tool via thelinkage arrangement, a plurality of valves associated with the pluralityof actuators, and a controller in communication with the first interfacedevice and the plurality of valves. The controller may be configured todetermine a combination of the plurality of actuators that should beactivated together to generate individual linkage movements thatcompound to produce the desired movement of the first work tool based onthe first work tool signal, and to selectively command movement of acombination of the plurality of valves corresponding to the combinationof the plurality of actuators.

A second aspect of the present disclosure is directed to a method ofcontrolling a machine having at least one arm arrangement. The methodmay include receiving a signal from an interface device indicative of adesired movement of a work tool connected to the at least one armarrangement, and determining a combination of actuators that should beactivated to achieve the desired movement of the work tool. The methodmay also include selectively commanding movement of a combination ofcontrol valve elements corresponding to the combination of actuators.

A third aspect of the present disclosure is directed to a machine. Themachine may include an undercarriage, a frame pivotally connected to theundercarriage, and a swing motor configured to swing the frame relativeto the undercarriage. The machine may also include a boom connected topivot about a horizontal axis of the frame, a first arm arrangementconnected to an end of the boom, and a second arm arrangement connectedto a second end of the boom.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic illustration of an exemplary disclosed machine;and

FIG. 2 is an exemplary disclosed control system that may be used withthe machine of FIG. 1.

DETAILED DESCRIPTION

FIG. 1 illustrates an exemplary machine 10 having multiple systems andcomponents that cooperate to excavate, demolish, load, move, and/orotherwise process material (e.g., scrap metal, earthen material,landfill material, roadway debris, etc.). In the depicted example,machine 10 is a hydraulic excavator. It is contemplated, however, thatmachine 10 could alternatively embody another type of excavation ormaterial handling machine, such as a backhoe, a front shovel, a draglineshovel, a crane, or another similar machine. Machine 10 may include,among other things, an implement system 12 that is configured to movemultiple work tools 14 between different locations and/or to actuatework tools 14. Machine 10 may also include an operator station 16 formanual control of implement system 12.

Implement system 12 may include many different fluid actuators thatinteract with various linkage components to independently and/orcooperatively move work tools 14. In particular, implement system 12 mayinclude a single common boom 18 having a pair of associated hydrauliccylinders 20, and two different arm arrangements 22, 24 that areoperatively connected to boom 18. Arm arrangements 22, 24 may besubstantially identical to each other or have different configurations,as desired. In the disclosed embodiment, each of arm arrangements 22,includes a boom link 26 having an associated hydraulic cylinder 28, apivot link 30 having an associated hydraulic cylinder 32 (not shown inFIG. 1 for arm arrangement 24), and a tool link 34 having an associatedhydraulic cylinder 36.

Boom 18 may be pivotally connected at a base end to a frame 38 ofmachine 10, while frame 38 may be pivotally connected to anundercarriage 40. Hydraulic cylinders 20 may cooperate to raise andlower boom 18 relative to frame 38, while a swing motor 42 may functionto swing frame 38 about a vertical axis 44 relative to undercarriage 40.A first end of each boom link 26 may be pivotally connected to a distalend of boom 18 and selectively pivoted about a horizontal axis 46 byhydraulic cylinder 28. Each pivot link 30 may be connected to a secondend of each boom link 26 and selectively pivoted about a vertical axis48 by hydraulic cylinder 32. Each tool link 34 may be connected at anopposing end of each pivot link 30 and selectively pivoted about ahorizontal axis 50 by hydraulic cylinder 36. Work tool 14 may beconnected to the remaining end of tool link 34 and selectively pivotedabout a horizontal axis 52 by an additional hydraulic cylinder 54. It iscontemplated that a greater or lesser number of fluid actuators and/orlinkage components may be included within implement system 12, and/orconnected in a manner other than described above, if desired.

Numerous different work tools 14 may be attachable to a single machine10 and controllable via operator station 16. Work tool 14 may includeany device used to perform a particular task such as, for example, abucket, a fork arrangement, a blade, a shovel, a crusher, a shear, agrapple, a magnet, a hammer, or any other task-performing device knownin the art. In the embodiment of FIG. 1, two similar work tools 14 areconnected to implement system 12 (e.g., one work tool 14 to each of armarrangements 22, 24), but each is connected in a different way.Specifically, work tool 14 associated with arm arrangement 22 is abucket connected to function as a typical excavator bucket, wherein theassociated digging motion is in a downward direction. In contrast,although work tool 14 associated with arm arrangement 24 is also abucket, the associated digging motion is in an upward direction as in afront shovel application. In other words, work tool 14 may be connectedto arm arrangement 22 in an opposite orientation relative to theconnection of work tool 14 with arm arrangement 24. It should be notedthat two completely different work tools 14 may be connected to armarrangements 22, 24 at any given time, as desired. In addition, althoughconnected in the embodiment of FIG. 1 to lift, swing, pivot, tilt, andcurl relative to machine 10, work tool(s) 14 may alternatively oradditionally rotate, slide, extend, open/close, and/or move in anothermanner known in the art.

In the example of FIG. 1, because one work tool 14 is configured tofunction as an excavator bucket and the other work tool 14 is configuredto function as a front shovel bucket, the connections of hydrauliccylinders 36 and 54 to the corresponding linkage components may bedifferent between arm arrangements 22, 24. In particular, hydrauliccylinders 36 and 54 of arm arrangement 22 are located at a side of pivotand tool links 30, 34 opposite the ground surface upon which machine 10is located. This is because the digging direction of arm arrangement 22may be primarily downward toward the ground surface and, by beinglocated at the opposite side of pivot and tool links 30, 34, hydrauliccylinders 36, 54 may be protected from collision with the excavatedmaterial and/or ground surface. For the same reason, hydraulic cylinders36, 54 of arm arrangement 24 are located at a side of pivot and toollinks 30, 34 opposite a vertical wall being excavated by machine 10. Itis contemplated that the placement of hydraulic cylinders 36, 54 withinarm arrangements 22, 24 could be identical, if desired.

Operator station 16 may be configured to receive input from a machineoperator indicative of desired work tool movements. Specifically,operator station 16 may include at least one interface device 56associated with each arm arrangement 22, 24. Each interface device 56may embody, for example, a multi-axis device located near an operatorseat (not shown). In the disclosed embodiment, interface device 56 maybe generally hemispherical, having an outer curved surface that isconfigured to fit into the operator's palm, although any other desiredshape (e.g., a shape resembling the shape of work tool 14) mayalternatively be utilized. Interface devices 56 may be proportional-typecontrollers configured to position and/or orient work tools 14 byproducing work tool position signals that are indicative of desired worktool speeds and/or forces in particular directions. The position signalsmay be used to simultaneously actuate any one or more of hydrauliccylinders 20, 28, 32, 36, 54 and/or swing motor 42.

In the disclosed embodiment, manipulation of interface devices 56 may bedirectly related to a desired motion of work tool 14 and not necessarilyto motion of individual hydraulic actuators. For example, tilting aparticular interface device 56 fore and aft about a base axis 58 maygenerate a first signal indicative of a desire to raise and lower worktool 14, regardless of the motion of other linkage components.Similarly, pivoting the same interface device 56 fore and aft about awrist axis 60 may generate a second signal indicative of a desire tocurl work tool 14 in and out. Tilting interface device 56 left and rightabout a base axis 62 may generate a third signal indicative of a desireto swing work tool 14, while pivoting interface device 56 left and rightabout a wrist axis 64 may generate a fourth signal indicative of adesire to pivot work tool 14 left and right. Twisting interface device56 about a vertical axis 66 may generate a fifth signal indicative of adesire to move work tool 14 inward toward our outward away from frame38.

It should be noted that interface device 56 may take a different form,if desired, and/or that interface device 56 may be moved in a differentway to generate any one or more of the first-fifth signals, if desired.It is further contemplated that one or more of the first through fifthsignals could alternatively be generated by movement of a differentinterface device 56, for example by movement of a foot pedal or bymanipulation of a button or switch that may or may not be associatedwith interface device 56.

Any one of the manually generated requests for work tool motion receivedvia interface device 56 may be caused within work tool 14 by actuating acombination of different hydraulic actuators, and the first-fifthsignals may not necessarily be directly related to use of any oneparticular hydraulic actuator. For example, to move work tool 14 awayfrom machine 10, hydraulic cylinders 20 may be retracted, hydrauliccylinder 28 may be extended, and/or hydraulic cylinder 36 may beextended. Similarly, to raise work tool 14, hydraulic cylinders 20 maybe extended, hydraulic cylinder 28 may be extended, and/or hydrauliccylinder 36 may be extended. To curl work tool 14 inward, hydrauliccylinders 20 may be extended, hydraulic cylinder 28 may be extended,hydraulic cylinder 36 may be extended, and/or hydraulic cylinder 54 maybe extended. To swing work tool 14, hydraulic cylinder 32 may beextended or retracted, and/or swing motor 42 may be activated.Accordingly, any combination of hydraulic cylinders 20-54 and swingmotor 42 may be selectively actuated in response to the signals frominterface device 56 to achieve a particular operator requested movementof work tool 14, and there may be more than one way to activatehydraulic cylinders 20-54 and swing motor 42 to achieve the desired worktool movement.

As illustrated in FIG. 2, machine 10 may include a control system 68having a plurality of components that cooperate to move work tools 14(referring to FIG. 1) in response to signals from interface devices 56.In particular, control system 68 may include a controller 70 incommunication with interface devices 56, and various control valvesresponsible for regulating the motion of hydraulic cylinders 20-54 andswing motor 42. The control valves may include, among others, a boomcontrol valve 72, two boom link control valves 74, two pivot linkcontrol valves 76, two tool link control valves 78, two tool controlvalves 80, and one swing control valve 82. Controller 70 may beconfigured to selectively cause control valves 72-82 to affect movementof their corresponding actuators based on the signals generated byinterface devices 56.

Each of control valves 72-82 may regulate the motion of their relatedfluid actuators in response to commands issued by controller 70.Specifically, boom control valve 72 may have elements movable to controlthe motion of hydraulic cylinders 20 associated with boom 18; boom linkcontrol valve 74 may have elements movable to control the motion ofhydraulic cylinder 28 associated with boom link 26; pivot link controlvalve 76 may have elements movable to control the motion of hydrauliccylinder 32 associated with pivot link 30; tool link control valve 78may have elements movable to control the motion of hydraulic cylinder36; and tool control valve 80 may have elements movable to control themotion of hydraulic cylinder 54. Likewise, swing control valve 82 mayhave elements movable to control the motion of swing motor 42. Thecontrol elements of each of control valves 72-82 may selectively becaused to move and thereby allow pressurized fluid to flow to and drainfrom their respective actuators. This fluid flow into and out of theactuators may result in movement of the actuators at desired speeds andwith desired forces in desired directions.

Because the elements of control valves 72-82 may be similar and functionin a related manner, only the operation of boom control valve 72 will bediscussed in this disclosure. In one example, boom control valve 72 mayinclude a first chamber supply element (not shown), a first chamberdrain element (not shown), a second chamber supply element (not shown),and a second chamber drain element (not shown). The first and secondchamber supply elements may be connected in parallel with a fluid source(e.g., a pump—not shown), while the first and second chamber drainelements may be connected in parallel with a drain (e.g., a tank—notshown). To extend hydraulic cylinders 20, the first chamber supplyelement may be moved to allow the pressurized fluid from the source tofill the first chambers of hydraulic cylinders 20, while the secondchamber drain element may be moved to drain fluid from the secondchambers of hydraulic cylinders 20. To move hydraulic cylinders 20 inthe opposite direction, the second chamber supply element may be movedto fill the second chambers of hydraulic cylinders 20 with pressurizedfluid, while the first chamber drain element may be moved to drain fluidfrom the first chambers of hydraulic cylinders 20. It is contemplatedthat both the supply and drain functions may alternatively be performedby a single element associated with the first chamber and a singleelement associated with the second chamber, or by a single element thatcontrols all filling and draining functions.

The supply and drain elements may be solenoid movable in response to acommand from controller 70. In particular, hydraulic cylinders 20, 28,32, 36, 55 and swing motor 42 may move at velocities that correspond tothe flow rates of fluid into and out of the first and second chambers,and with forces that correspond to pressure differentials across therespective actuators. To achieve the operator-desired velocity and/orforce of work tool 14 indicated via the interface device positionsignal, a command based on an assumed or measured pressure may be sentto a combination of solenoids (not shown) of the supply and drainelements that causes them to open an amount corresponding to thenecessary flow rates and/or pressures. The command may be in the form ofa flow rate command or a valve element position command generated bycontroller 70.

Controller 70 may embody a single microprocessor or multiplemicroprocessors that include a means for controlling an operation ofcontrol system 68. Numerous commercially available microprocessors canbe configured to perform the functions of controller 70. It should beappreciated that controller 70 could readily be embodied in a generalmachine microprocessor capable of controlling numerous machinefunctions. Controller 70 may include a memory, a secondary storagedevice, a processor, and any other components for running anapplication. Various other circuits may be associated with controller 70such as power supply circuitry, signal conditioning circuitry, solenoiddriver circuitry, and other types of circuitry.

One or more maps relating the interface device position signals (i.e.,the desired movement of work tool 14) to required actuator forces and/orvelocities may be stored in the memory of controller 70. Likewise, thesame or other maps relating the required actuator forces and/orvelocities to corresponding valve element positions for control valves72-82 may also be stored in the memory of controller 70. Each of thesemaps may include a collection of data in the form of tables, graphs,and/or equations.

Controller 70 may be configured to receive input from the operator ofmachine 10 via interface devices 56, and to command operation of controlvalves 72-82 in response to the input and the selected relationship mapsdescribed above. For example, controller 70 may receive an interfacedevice position signal indicative of a desired force and/or velocity ofwork tool 14 in a desired direction, and reference the firstrelationship map from the maps stored in the memory of controller 70 todetermine which combination of actuators (i.e., which one or more ofhydraulic cylinders 20, 28, 32, 36, 54 and/or swing motor 42) should beactivated together to produce individual linkage movements that compoundto produce the requested movement. In some instances, there may be morethan one combination of actuators that could be used to achieve thedesired work tool movement. In these situations, controller 70 mayevaluate the different possible combinations and pick the onecombination that best achieves the desired movement according to one ormore predefined goals (e.g., efficiency goals, actuator priority goals,time goals, etc.). Controller 70 may then reference the secondrelationship map to determine flow rate values and/or associatedpositions for each of the supply and drain elements within particularcontrol valves 72-82 related to the selected combination of actuators.The flow rates or positions may then be commanded of the appropriatesupply and drain elements to cause filling and/or draining of variouspressure chambers at rates that result in the desired work tool forceand/or velocity in the desired direction.

In some applications, during simultaneous use of the first and secondarm arrangements 22, 24, if not otherwise accounted for, it may bepossible for work tools 14 and/or other associated actuators or links tocollide with each other. Accordingly, in these applications, controller70 may be configured to impose virtual limits on movements of someportions or all of first and/or second arm arrangements 22, 24 so as toavoid these collisions. In other embodiments, it may not be physicallypossible for first arm arrangement 22 to collide with second armarrangement 24. For example, one or more mechanical stops (not shown)may be provided to limit the movements of first and/or second armarrangements 22, 24.

INDUSTRIAL APPLICABILITY

The disclosed control system may be applicable to any tool-carryingexcavation machine. The disclosed system may provide tool useversatility, while still allowing for high-power lifting operations witha single boom. In addition, the disclosed control system may provide fora simple way to control the different links and associated hydraulicactuators and achieve desired work tool movements.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the disclosed controlsystem. Other embodiments will be apparent to those skilled in the artfrom consideration of the specification and practice of the disclosedcontrol system. It is intended that the specification and examples beconsidered as exemplary only, with a true scope being indicated by thefollowing claims and their equivalents.

What is claimed is:
 1. A control system, comprising: a first work toolconnected at an end of a linkage arrangement; a first interface deviceconfigured to receive input from an operator indicative of a desiredmovement of the first work tool and to generate a corresponding firstwork tool signal; a plurality of actuators operatively connected to thefirst work tool via the linkage arrangement; a plurality of valvesassociated with the plurality of actuators; and a controller incommunication with the first interface device and the plurality ofvalves, the controller being configured to: determine a combination ofthe plurality of actuators that should be activated together to generateindividual linkage movements that compound to produce the desiredmovement of the first work tool based on the first work tool signal; andselectively command simultaneous movement of a combination of theplurality of valves corresponding to the combination of the plurality ofactuators.
 2. The control system of claim 1, wherein: the desiredmovement of the first work tool may be achieved by more than onecombination of the plurality of actuators; and the controller is furtherconfigured to select one of the more than one combination for activationthat best achieves the desired movement of the first work tool accordingto one or more predefined goals.
 3. The control system of claim 2,wherein the one or more predefined goals is associated with at least oneof efficiency, actuator priority, and time.
 4. The control system ofclaim 1, wherein the plurality of actuators includes: a pair ofhydraulic cylinders associated with a boom; a third hydraulic cylinderassociated with a first boom link connected to the boom; a fourthhydraulic cylinder associated with a first pivot link connected to thefirst boom link; a fifth hydraulic cylinder associated with a first toollink connected to the first pivot link; a sixth hydraulic cylinderassociated with the first work tool and the first tool link; and a swingmotor connected between a machine frame and an undercarriage.
 5. Thecontrol system of claim 4, wherein the third, fourth, fifth, and sixthhydraulic cylinders, together with the first boom link, the first pivotlink, the first tool link, and the first work tool are grouped into afirst arm arrangement controllable by the first interface device.
 6. Thecontrol system of claim 5, wherein: the control system further includesa second work tool; the plurality of actuators further includes: aseventh hydraulic cylinder associated with a second boom link connectedto the boom; an eighth hydraulic cylinder associated with a second pivotlink connected to the second boom link; a ninth hydraulic cylinderassociated with a second tool link connected to the second pivot link;and a tenth hydraulic cylinder associated with the second work tool andthe second tool link; and the seventh, eighth, ninth, and tenthhydraulic cylinders, together with the second boom link, the secondpivot link, the second tool link, and the second work tool are groupedinto a second arm arrangement.
 7. The control system of claim 6, furtherincluding a second interface device associated with the second armarrangement.
 8. The control system of claim 6, wherein: the third andseventh hydraulic cylinders are located at the same general locationsrelative to the first and second boom links; and the fourth and eighthhydraulic cylinders are located at the same general locations relativeto the first and second pivot links.
 9. The control system of claim 8,wherein: the fifth and ninth hydraulic cylinders are located atgenerally opposite locations relative to the first and second toollinks; and the sixth and tenth hydraulic cylinders are located atgenerally opposite locations relative to the first and second worktools.
 10. The control system of claim 6, wherein: the third, fifth,sixth, seventh, ninth, and tenth hydraulic cylinders are configured topivot the first and second work tools about horizontal axis,respectively; and the fourth and eighth hydraulic cylinders areconfigured to pivot the first and second work tools about vertical axis,respectively.
 11. The control system of claim 6, wherein the controlleris further configured to inhibit collision of first and second armarrangements.
 12. A method of controlling a machine having at least onearm arrangement, the method comprising: receiving a signal from aninterface device indicative of a desired movement of a work toolconnected to the at least one arm arrangement; determining a combinationof actuators that should be activated to achieve the desired movement ofthe work tool; and selectively commanding movement of a combination ofcontrol valve elements corresponding to the combination of actuators.13. The method of claim 12, wherein determining a combination ofactuators includes: determining more than one combination of actuatorsthat could be activated to achieve the desired movement of the worktool; and selecting one of the more than one combination for activationthat best achieves the desired movement of the work tool according toone or more predefined goals.
 14. The method of claim 13, wherein theone or more predefined goals is associated with at least one ofefficiency, actuator priority, and time.
 15. The method of claim 12,wherein: receiving the signal includes receiving a first signal from afirst interface device indicative of a desired movement of a first worktool connected to a first arm arrangement, and receiving a second signalfrom a second interface device interface device indicative of a desiredmovement of a second work tool connected to a second arm arrangement;determining a combination of actuators includes determining a firstcombination of actuators that should be activated to achieve the desiredmovement of the first work tool and determining a second combination ofactuators that should be activated to achieve the desired movement ofthe second work tool; and selectively commanding movement of first andsecond combinations of control valve elements corresponding to the firstand second combinations of actuators.
 16. A machine, comprising: anundercarriage; a frame pivotally connected to the undercarriage; a swingmotor configured to swing the frame relative to the undercarriage; aboom connected to pivot about a horizontal axis relative to the frame; afirst arm arrangement connected to an end of the boom; and a second armarrangement connected to a second end of the boom.
 17. The machine ofclaim 16, wherein each of the first and second arm arrangementsincludes: a boom link; a first hydraulic cylinder connecting the boomlink to the boom; a pivot link; a second hydraulic cylinder connectingthe pivot link to the boom link; a tool link; a third hydraulic cylinderconnecting the tool link to the pivot link; a work tool; and a fourthhydraulic cylinder connecting the work tool to the tool link.
 18. Themachine of claim 17, wherein: the first, third, and fourth hydrauliccylinders are configured to pivot the work tool about horizontal axis;and the second hydraulic cylinder is configured to pivot the work toolabout a vertical axis.
 19. The machine of claim 17, wherein third andfourth hydraulic cylinders of the first arm arrangement are locatedopposite the third and fourth hydraulic cylinders of the second armarrangement.
 20. The machine of claim 19, wherein the work tool of thefirst arm arrangement is oriented opposite the work tool of the secondarm arrangement.